Android 从SQLite迁移到Room：迁移没有'；我拿不好桌子

所以我使用的是SQLite数据库，现在我决定将它迁移到Room，而不做任何更改。这就是我的房间模型

@Entity(tableName = "documents")
data class Document(
    @PrimaryKey(autoGenerate = true)
    val docID: Int,
    val path: String,
    val filename: String,
    val dateCreated: Long = MAX_VALUE,
)

这是我用来在room之前创建表的查询：

"CREATE TABLE IF NOT EXISTS documents (docID INTEGER PRIMARY KEY ASC, path TEXT NOT NULL unique, filename TEXT NOT NULL, dateCreated LONG DEFAULT MAX_VALUE)"

另外，我创建了一个到数据库最终版本的新迁移，该数据库使用了这个房间，我将它留空，因为我不想更改表中的任何内容

private val MIGRATION_9_10: Migration = object : Migration(9, 10) {
    override fun migrate(database: SupportSQLiteDatabase) {

    }
}

因此，当我最终在设备上运行它时（该设备具有数据库的早期（9）版本），会引发一个异常：

java.lang.IllegalStateException: Migration didn't properly handle: documents.

路径字段和文件名字段的类型不同，预期为文本，但实际上为字符串，日期创建的类型也不同，预期为整数，但实际为长。对我来说，有趣的是dateCreated早就属于long类型，现在仍然是long类型。我尝试添加迁移，如下所示：

private val MIGRATION_9_10: Migration = object : Migration(9, 10) {
    override fun migrate(database: SupportSQLiteDatabase) {
        val tableDocumentsTemp = "documents_temp"
        database.execSQL("ALTER TABLE documents RENAME TO $tableDocumentsTemp")
        database.execSQL("CREATE TABLE documents (docId INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, path STRING NOT NULL, filename STRING NOT NULL, dateCreated LONG DEFAULT $MAX_VALUE)")
        database.execSQL("INSERT INTO documents (docId, path, filename, dateCreated) SELECT docId, path, filename, dateCreated FROM $tableDocumentsTemp")
        database.execSQL("DROP TABLE $tableDocumentsTemp")
        }
    }
}

但这没什么区别

---

有人知道我如何修复它吗？

在编写room数据库迁移代码时，必须使用文本作为字符串，使用整数作为长数据类型

private val MIGRATION_9_10: Migration = object : Migration(9, 10) {
override fun migrate(database: SupportSQLiteDatabase) {
    val tableDocumentsTemp = "documents_temp"
    database.execSQL("CREATE TABLE $tableDocumentsTemp (docId INTEGER NOT NULL, path TEXT NOT NULL, filename TEXT NOT NULL, dateCreated INTEGER DEFAULT $MAX_VALUE NOT NULL, PRIMARY KEY(docId))")
    database.execSQL("INSERT INTO $tableDocumentsTemp (docId, path, filename, dateCreated) SELECT docId, path, filename, dateCreated FROM documents")
    database.execSQL("DROP TABLE documents")
    database.execSQL("ALTER TABLE $tableDocumentsTemp RENAME TO documents")
    }
 }
}

private val MIGRATION_9_10: Migration = object : Migration(9, 10) {
override fun migrate(database: SupportSQLiteDatabase) {
    val tableDocumentsTemp = "documents_temp"
    database.execSQL("CREATE TABLE $tableDocumentsTemp (docId INTEGER NOT NULL, path TEXT NOT NULL, filename TEXT NOT NULL, dateCreated INTEGER DEFAULT $MAX_VALUE NOT NULL, PRIMARY KEY(docId))")
    database.execSQL("INSERT INTO $tableDocumentsTemp (docId, path, filename, dateCreated) SELECT docId, path, filename, dateCreated FROM documents")
    database.execSQL("DROP TABLE documents")
    database.execSQL("ALTER TABLE $tableDocumentsTemp RENAME TO documents")
    }
 }
}